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1
Content available Heat transfer study from square cylinder immersed in water-based nanofluid: Effect of orientation
Kaur Jaspinder, Ratar Jatinder Kumar, Tiwari Anurag Kumar
Chemical and Process Engineering
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2022
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Vol. 43, nr 2
243-–250
EN
Heat transfer study from the heated square cylinder at a different orientation angle to the stream of nanofluids has been investigated numerically. CuO-based nanofluids were used to elucidate the significant effect of parameters: Reynolds number (1–40), nanoparticle volume fraction (0.00–0.05), the diameter of the NPs (30–100 mn) and the orientation of square cylinder (0–90). The numerical results were expressed in terms of isotherm contours and average Nusselt number to explain the effect of relevant parameters. Over the range of conditions, the separation of the boundary layers of nanofluids increased with the size of the NPs as compared to pure water. NPs volume fraction and its size had a significant effect on heat transfer rate. The square cylinder of orientation angle (45) gained a more efficient heat transfer cylinder than other orientation angles. Finally, the correlations were developed for the average Nusselt number in terms of the relevant parameters for 45 orientation of the cylinder for new applications.
2
Content available Enhancement of heat transfer in helical coil heat exchangers using nano-fluids
Parveez Malik, Hanief Mohammad
Chemical and Process Engineering
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2022
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Vol. 43, nr 2
279--283
EN
Investigation for heat transfer behaviour of Al2O3 and CuO nano-fluid in helical coil heat exchangers was carried out in this study. The thermo-physical properties of the fluids have temperature dependent nature. The main emphasis was to depict the influence of nano-particle concentration by volume on the characteristics of temperature, rate of heat transfer and heat transfer coefficients (convective). In order to enhance efficiency, density and thermal conductivity are considered to be the most important variables. In comparison to water and for equal flow rate, the rate of heat transfer of nano-fluid increases conspicuously. Efficiency of the helical coil heat exchanger increased by 38.80%.
3
Content available Anisotropic turbulent viscosity and large-scale motive force in thermally driven turbulence at low Prandtl number
Mizerski K. A.
Archives of Mechanics
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2022
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Vol. 74, nr 5
409-436
EN
The fully developed turbulent Boussinesq convection is known to form large-scale rolls, often termed the ‘large-scale circulation’ (LSC). It is an interesting question how such a large-scale flow is created, in particular in systems when the energy input occurs at small scales, when inverse cascade is required in order to transfer energy into the large-scale modes. Here, the small-scale driving is introduced through stochastic, randomly distributed heat source (say radiational). The mean flow equations are derived by means of simplified renormalization group technique, which can be termed a ‘weakly nonlinear renormalization procedure’ based on consideration of only the leading order terms at each step of the recursion procedure, as full renormalization in the studied anisotropic case turns out unattainable. The effective, anisotropic viscosity is obtained and it is shown that the inverse energy cascade occurs via an effective ‘motive force’ which takes the form of transient negative, vertical diffusion.
4
Content available Numerical predictions of laminar flow and free convection heat transfer from an isothermal vertical flat plate
Belhocine Ali, Stojanovic Nadica, Abdullah Oday Ibraheem
Archive of Mechanical Engineering
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2022
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LXIX, nr 4
749--773
EN
In this present work, the laminar free convection boundary layer flow of a two-dimensional fluid over the vertical flat plate with a uniform surface temperature has been numerically investigated in detail by the similarity solution method. The velocity and temperature profiles were considered similar to all values and their variations are as a function of distance from the leading edge measured along with the plate. By taking into account this thermal boundary condition, the system of governing partial differential equations is reduced to a system of non-linear ordinary differential equations. The latter was solved numerically using the Runge-Kutta method of the fourth-order, the solution of which was obtained by using the FORTRAN code on a computer. The numerical analysis resulting from this simulation allows us to derive some prescribed values of various material parameters involved in the problem to which several important results were discussed in depth such as velocity, temperature, and rate of heat transfer. The definitive comparison between the two numerical models showed us an excellent agreement concerning the order of precision of the simulation. Finally, we compared our numerical results with a certain model already treated, which is in the specialized literature.
5
Content available Unsteady MHD natural convective boundary layer flow and heat transfer over a truncated cone in the presence of pressure work
Ajay C. K., Srinivasa A. H.
Journal of Applied Mathematics and Computational Mechanics
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2020
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Vol. 19, nr 1
5--16
EN
The aim of the present paper is to analyse the effect of MHD on unsteady natural convection boundary layer flow and heat transfer over a truncated cone in the presence of pressure work. Suitable transformation is utilized to form a system of coupled non-linear partial differential equations for governing both the flow and heat transfer. These equations have been solved numerically by utilizing an implicit finite difference scheme along with quasilinearization method. Here, the computed numerical results are displayed graphically in terms of the local Nusselt number, skin friction, temperature distribution, and velocity distribution for various values of the magnetic and pressure work parameters along with the fixed Prandtl number
6
Content available Vertical heat transport at infinite Prandtl number for micropolar fluid
Caggio M., Kalita P., Łukaszewicz G., Mizerski K. A.
Archives of Mechanics
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2020
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Vol. 72, nr 6
525--553
EN
We investigate the upper bound on the vertical heat transport in the fully 3D Rayleigh–Bénard convection problem at the infinite Prandtl number for a micropolar fluid. We obtain a bound, given by the cube root of the Rayleigh number, with a logarithmic correction. The derived bound is compared with the optimal known one for the Newtonian fluid. It follows that the (optimal) upper bound for the micropolar fluid is less than the corresponding bound for the Newtonian fluid at the same Rayleigh number. Moreover, strong microrotational diffusion effects can entirely suppress the heat transfer. In the Newtonian limit our purely analytical findings fully agree with estimates and scaling laws obtained from previous theories significantly relying on phenomenology.
7
Content available Combined effects of Soret and Dufour on MHD flow of a power-law fluid over flat plate in slip flow rigime
Saritha K., Rajasekhar M. N., Reddy B. S.
International Journal of Applied Mechanics and Engineering
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2018
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Vol. 23, no. 3
689--705
EN
A numerical model is developed to study the Soret and Dufour effects on MHD boundary layer flow of a power-law fluid over a flat plate with velocity, thermal and solutal slip boundary conditions. The governing equations for momentum, energy and mass are transformed to a set of non-linear coupled ordinary differential equations by using similarity transformations. These non-linear ordinary differential equations are first linearized using a quasi-linearization technique and then solved numerically based on the implicit finite difference scheme over the entire range of physical parameters with appropriate boundary conditions. The influence of various governing parameters along with velocity, thermal and mass slip parameters on velocity, temperature and concentration fields are examined graphically. Also, the effects of slip parameters, the Soret and Dufour number on the skin friction, Nusselt number and Sherwood number are studied. Results show that the increase in the Soret number leads to a decrease in the temperature distribution and to an increase in concentration fields.
8
Content available A numerical study of coupled non-linear equations of thermo-viscous fluid flow in cylindrical geometry
Pothanna N., Aparna P., Gorla R. S. R.
International Journal of Applied Mechanics and Engineering
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2017
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Vol. 22, no. 4
965--979
EN
In this paper we present numerical solutions to coupled non-linear governing equations of thermo-viscous fluid flow in cylindrical geometry using MATHEMATICA software solver. The numerical results are presented in terms of velocity, temperature and pressure distribution for various values of the material parameters such as the thermo-mechanical stress coefficient, thermal conductivity coefficient, Reiner Rivlin cross viscosity coefficient and the Prandtl number in the form of tables and graphs. Also, the solutions to governing equations for slow steady motion of a fluid have been obtained numerically and compared with the existing analytical results and are found to be in excellent agreement. The results of the present study will hopefully enable a better understanding applications of the flow under consideration.
9
Content available Hall effects on MHD flow past an accelerated plate with heat transfer
Sundarnath J. K., Muthucumarswamy R.
International Journal of Applied Mechanics and Engineering
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2015
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Vol. 20, no. 1
171--181
EN
Hall current and rotation on an MHD flow past an accelerated horizontal plate relative to a rotating fluid, In the presence of heat transfer has been analyzed. The effects of the Hall parameter, Hartmann number, rotation parameter (non-dimensional angular velocity), Grashof’s number and Prandtl number on axial and transverse velocity profiles are presented graphically. It is found that with the increase in the Hartmann number, the axial and transverse velocity components increase in a direction opposite to that of obtained by increasing the Hall parameter and rotation parameter. Also, when […], it is observed that the transverse velocity component vanishes and axial velocity attains a maximum value.
10
Content available The effects of inclination angle and Prandtl number on the mixed convection in the inclined lid driven cavity using lattice Boltzmann method
Karimipour A., Nezhad A. H., D’Orazio A., Shirani E.
Journal of Theoretical and Applied Mechanics
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2013
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Vol. 51 nr 2
447--462
EN
The laminar mixed convection in a two-dimensional rectangular inclined cavity with moving top lid is investigated using the double population thermal lattice Boltzmann method (LBM) at different values of the Richardson number, inclination angle and the Prandtl number. In this problem, velocity components are changed by both buoyancy forces and the inclination angle of the cavity. Comparison of the present results with other available data show good agreement. As the results, the velocity and temperature profiles, the Nusselt number, streamlines and isotherms are presented and discussed. It is shown that the increase of Prandtl number enhances the heat transfer rate, especially at higher values of inclination angle and Richardson number. Moreover, the average Nusselt number at the upper limit of the considered range of the Richardson and Prandtl numbers variability increases by a factor of 9.
PL
W pracy zajęto się problemem mieszanej konwekcji laminarnej w dwuwymiarowej, prostokątnej i ukośnie usytuowanej szczelinie domkniętej od góry ruchomą pokrywą. W badaniach zastosowano metodę siatki termicznej Boltzmanna (LBM) podwójnej populacji, uwzględniając rożne wartości liczby Richardsona, kąta pochylenia szczeliny oraz liczby Prandtla. W rozważanym zagadnieniu, składowe prędkości zostały poddane zmianom indukowanym siłami wyporu oraz kątem pochylenia szczeliny. Porównanie otrzymanych wynikow analizy z dostępnymi w literaturze danymi wykazało dobrą zgodność. Rezultatem badań w pracy są także profile rozkładu prędkości i temperatury, liczba Nusselta, linie prądu oraz izotermy, które szczegółowo przedyskutowano. Pokazano, że wzrost liczby Prandtla zwiększa transfer ciepła, zwłaszcza dla wyższych wartości kąta pochylenia szczelin i liczby Richardsona. Co więcej, średnia liczba Nusselta przy górnych wartościach przyjętego zakresu zmienności liczb Richardsona i Prandtla wzrasta 9-krotnie.
11
Content available remote Viscous dissipation effects on MHD flow of a conducting power-law fluid with a pressure gradient
Kishan N., Shashidar Reddy B.
International Journal of Applied Mechanics and Engineering
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2012
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Vol. 17, no. 1
101-112
EN
The problem of a steady two-dimensional flow of a conducting power-law fluid past a flat plate in the presence of a transverse magnetic field under the influence of a pressure gradient by considering viscous dissipation effects is studied. The resulting governing partial differential equations are transformed into a set of non linear ordinary differential equations using appropriate transformation. The set of non linear ordinary differential equations is first linearized by using the Quasi-linearization technique and then solved numerically by using an implicit finite difference scheme. The system of algebraic equations is solved by using the Gauss-Seidal iterative method. The energy equation for a special case for which a similarity solution exist is also considered. The effects of the power-law index, magnetic parameter, viscous dissipation and generalized Prandtl number on the velocity and temperature profiles are of special interest. Numerical results are tabulated for the skin friction co-efficient. Velocity and temperature profiles are drawn for different controlling parameters which reveal the tendency of the solution.
12
Content available remote Heat transfer in MHD viscoelastic boundary layer flow over an exponential stretching sheet
Nandeppanavar M. M., Subhas Abel M., Ravi S., Jyoti H.
International Journal of Applied Mechanics and Engineering
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2011
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Vol. 16, no 2
455-474
EN
An analysis has been carried out to study the steady viscoelastic hydromagnetic flow and heat transfer in a visco-elastic liquid flow over an exponentially stretching sheet with consideration of viscous dissipation. A zeroth order analytical local similar solution of the highly non-linear stream function equation and confluent hypergeometric solution of the heat transfer equation is obtained by converting the governing partial differential equation to ordinary differential equation by similarity transformations. The accuracy of the analytical solution for the stream function is verified by a numerical solution obtained by employing the Runge-Kutta fourth order method with shooting. The two following cases of surface conditions are studied, namely (1) prescribed exponential order surface temperature (PEST Case) and (2) prescribed exponential order boundary heat flux (PEHF Case). The effect of various parameters arising in the flow on momentum and heat transfer characteristics are presented graphically and the numerical results of wall temperature gradient (in PEST Case ) and wall temperature (PEHF Case ) are tabulated and compared with previous results.
13
Content available remote Heat transfer in a liquid film over an unsteady stretching surface with the effects of viscous dissipation, thermal radiation and non-uniform heat source in the presence of external magnetic field
Abel. M. S., Tawade J. V.
International Journal of Applied Mechanics and Engineering
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2010
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Vol. 15, no 4
967-992
EN
This paper presents a mathematical analysis of an MHD flow and heat transfer to a laminar liquid film from a horizontal stretching surface. The flow of a thin fluid film and subsequent heat transfer from the stretching surface is investigated with the aid of similarity transformation. The transformation renders it possible to reduce the unsteady boundary layer equations to a system of non-linear ordinary differential equations. A numerical solution of the resulting nonlinear differential equations which agrees well with the analytic solution, is obtained by the efficient shooting technique. The effects of boundary layer thickness on various physical parameters such as the unsteadiness parameter S and magnetic parameter Mn, Prandtl number Pr, Eckert number Ec, thermal radiation parameter Nr and non-uniform heat source/sink parameters which determine the temperature profiles, the heat transfer coefficient are tabulated and plotted in figures. It is shown that the heat fluxes from the liquid to the elastic sheet decreases with S for […] and increases with S for […]. Some important findings reported in this work reveal that the combined effect of thermal radiation and non-uniform heat source have significant impact on controlling the rate of heat transfer in the boundary layer region.
14
Content available remote Transient free-convective flow in a vertical channel due to symmetric heating
Jha B. K., Singh A. K., Takhar H. S.
International Journal of Applied Mechanics and Engineering
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2003
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Vol. 8, no 3
497-502
EN
This paper presents a closed form solution for a transient free convective flow of a viscous and incompressible fluid in a vertical channel due to symmetric heating of channel walls. The Laplace transform technique has been used to obtain the expression for the velocity and temperature fields by solving the governing differential equations. The influence of the physical parameters on the velocity field, skin-friction, rate of heat transfer and volumetric flux of the fluid are carefully analysed. A correlation between the steady state time and the Prandtl number has been developed. It is observed that the nature of correlation is linear when the Prandtl number is greater than one while cubic for the Prandtl number is less than one.
15
Content available remote Heat transfer over an exponentially stretching continuous surface with suction
Elbashbeshy E. M. A.
Archives of Mechanics
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2001
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Vol. 53, nr 6
643-651
EN
Similary solutions of the laminar boundary layer equations describing heat and flow in a quiescent fluid driven by an exponentially stretching surface subject to suction are examined numerically. The direction and amount of heat flow were found to be dependent on the magnitude of ... (parameter of temperature) for the same Prandtl number. Nusselt number increases with increasing ... and the Prandtl number. The effect of decreasing suction parameter is found to be significant particularly for the Prandtl number.
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